Geologic Hazards

Wyoming is known for its remarkable variety of natural landscapes. From snowcapped mountains to
deep canyons, high deserts to Yellowstone, Earth’s geologic processes constantly shape the Wyoming
landscape. These geological processes can be accountable for periodic and destructive geologic
hazards that can affect people and infrastructure. Geologic hazards in Wyoming are numerous and
vary widely from sudden events, such as earthquakes, landslides, and volcanic eruptions, to slow
processes such as windblown deposits and expansive soils.

►Earthquakes

Earthquakes occur daily in Wyoming but are often not strong enough for people to feel. Most of
the state’s earthquakes occur within the Yellowstone region and western Wyoming, however,
earthquakes do occur in other areas of the state. Quaternary faults are faults identified at the
earth’s surface that display evidence of movement in the past 2.6 million years. Faults are
considered to be Late Pleistocene-Holocene faults if there is evidence or observations of seismic
events in the last 15,000 years. Learn more about earthquakes.

►Landslides

Landslides can cause major losses to infrastructure, such as roads and property, causing
millions of dollars in damage. However, in Wyoming, most landslides occur in remote areas of
the state and do not typically cause damage. Learn more about landslides.

►Volcanic Eruptions

Volcanic eruptions can produce a variety of geologic hazards, including airborne debris (ash),
earthquakes, hot gasses, landslides, and hydrothermal explosions. Over the last 2 million years,
historic eruptions associated with the Yellowstone hot spot have covered vast areas of
North America with ash. The last major caldera-forming eruption to occur created the present day
Yellowstone caldera, approximately 640,000 years ago. Not all volcanic eruptions in Yellowstone
are catastrophic events. The most recent volcanic eruption, a lava flow creating the Pitchstone
Plateau, occurred 70,000 years ago. Learn more about the Yellowstone volcanic system.

►Expansive Soils

Expansive soils shrink and swell when subjected to changes in moisture. Highways, structures,
and utility lines are susceptible to damage from expansive soils, resulting in maintenance and
replacement costs. Learn more about expansive soils.

►Windblown Deposits

Windblown deposits form when sand, silt, or clay (loess) materials are transported by wind and
deposited on the ground surface. These deposits can cover roadways and agricultural lands and
encroach on structures. Stable windblown deposits (those that have become vegetated) may become
active again if they are disturbed and not properly re-vegetated or stabilized.
Learn more about windblown deposits.

The WSGS Geologic Hazards Group is focused on identifying and characterizing geologic hazards throughout the state. Hazard geologists carry out research, compile and analyze data, create hazard maps, produce reports, and address geologic hazards to better assist the public, state and federal agencies, and county planners.